Liquid crystal display devices are now widely mounted on various terminals, with their advantages utilized such as thin body, light weight, compact size, low power consumption, etc. Among liquid crystal display devices, active matrix type devices have a pixel electrode and a thin film transistor (TFT) or an active element connected to the pixel electrode in each of the pixel regions defined by signal lines and scanning lines laid in a matrix form. The liquid crystal display element is driven when a predetermined voltage is applied to the pixel electrode via the TFT.
In conventional active matrix liquid crystal display devices, the gap between a signal line and a pixel electrode adjacent to the signal line is small, and so-called vertical crosstalk occurs due to parasitic capacitance that occurs between the signal line and the pixel electrode, leading to a problem that the image quality degenerates.
Compared to this, Patent Literature 1 discloses an electrode structure that reduces parasitic capacitance in a transparent liquid crystal display device. FIG. 13 is a partial cross section of a conventional active matrix substrate described in Patent Literature 1. As shown in FIG. 13, a metal film 102 is formed on a glass substrate 101, and an insulating film 103 is formed to cover the metal film 102 and the glass substrate 101. A source line 104 or a signal line is formed above the metal film 102 via the insulating film 103, and another insulating film 105 is formed to cover the source line 104 and the insulating film 103. A pair of pixel electrodes 106 adjoining each other are formed on the insulating film 105. According to this conventional technique, the edge portions of the metal film 102 and the pixel electrodes 106 overlap when seen in the plan-view perspective, while the widthwise edges of the source line 104 and the pixel electrodes 106 do not overlap in the plan-view perspective.
In this structure, the parasitic capacitance that occurs between the pixel electrodes 106 and the source line 104 series of the capacitance between the pixel electrodes 106 and the metal film 102 and the capacitance between the metal film 102 and the source line 104. Therefore, the parasitic capacitance that influences the pixel electrodes 106 can be reduced. As a result, an effect that contrast improves is obtained.    Patent Literature 1: Unexamined Japanese Patent Application KOKAI Publication No. H5-142570.